Why truck platooning surged then stalled, what pilots really proved, and how the lessons guide today’s autonomy roadmaps.
Good technology sometimes arrives before the ecosystem is ready for it, or works great in pilots but fails when rubber hits the road. In the mid 2010s, platooning looked ready for primetime. It proved the physics: 4 to 6 percent fuel savings in controlled tests, with NREL hitting 6.4 percent at highway speeds. Pilots ran in the U.S. and Europe. Fleets were curious. Then the real world showed up: variable routes, regulatory patchwork, split incentives, and ROI that did not come to life in the real world. However, while platooning didn't scale, what it taught us did.
What is Platooning?
Platooning links trucks through vehicle-to-vehicle communication (V2V) so throttle and braking coordinate automatically. Most real pilots used two trucks with drivers in both cabs, often described as cooperative adaptive cruise control. Following distances ranged from roughly 30 to 50 feet when conditions allowed. Europe also trialed longer multi‑brand platoons, but commercial efforts largely focused on two‑truck formations with human oversight [FMCSA, 2018; ENSEMBLE, 2022].
Why fleets were curious
Why the interest? Fuel and safety. Instrumented tests suggested combined savings clustering near 4 to 6 percent depending on speed, weight, and gap. NREL’s controlled work and later road studies set expectations for where savings show up and where they do not [NREL, 2014; NREL, 2018].
In Europe, the ENSEMBLE program aligned multiple OEMs on a common approach and demonstrated cross‑brand operations. ENSEMBLE differentiated between a driver‑support function (PSF, larger headways) and an automation‑heavy future concept (PAF, smaller gaps between hubs) [ENSEMBLE, 2022].
Public pilots continued in the U.S. as states created exemptions for closer following. In 2025, Ohio and Indiana began corridor operations on I‑70 with leader‑follower automation, gathering on‑road data under driver supervision [NCSL, 2025; DriveOhio/INDOT, 2025].
Why It Stalled: A fleet‑first view
Operational fit
Platooning thrives on steady speeds and consistent pairing. Real operations bring trailer swaps, variable departures, weather, grades, and traffic cut‑ins. NREL found that savings drop with higher speeds, heavier gross weights, lateral offsets, and mixed traffic effects. Cooling fan events on the follower and time lost to staging can erode gains [NREL, 2014; NREL, 2020].
Human factors
Drivers must be comfortable with close headways for long stretches while managing surrounding traffic. FHWA research highlighted the role of clear indicators and signage for other motorists and the need to monitor workload and acceptance over longer routes. ENSEMBLE recommended larger gaps near on‑ramps and cautioned about complexity around merges [FHWA, 2021; ENSEMBLE, 2022].
Regulatory and communications
States moved at different speeds. Many created exemptions to traditional following‑distance rules, often with conditions or limits that complicated multi‑state routes. This patchwork raised planning costs [NCSL, 2025]. Communications added a second layer. In 2020 the FCC reallocated the 5.9 GHz band, leaving 30 MHz for safety and setting a path toward cellular vehicle-to-anything communication (C-V2X) . In 2024 it codified C‑V2X technical rules. DSRC‑based roadmaps had to adjust, and industry waited for clarity on device rules and deployment guidance [FCC, 2020; FCC, 2024].
Economics
Who captures the savings? The follower typically saves more fuel. Cross‑fleet pairing created tricky alignment questions, even within the same fleets. Some OEMs assessed real‑world results and pressed pause. In 2019, Daimler reported there was no U.S. long‑haul business case at the time, citing cut‑ins and modern aerodynamics that narrowed the fuel delta [Supply Chain Dive, 2019]. ENSEMBLE’s PSF demonstrations at roughly 1.4 to 1.7 seconds of headway showed little to no fuel benefit on many roads, reinforcing that tighter, automation‑enabled gaps would be required for material savings in Europe [ENSEMBLE, 2022].
What Endures from the Platooning Era
Three durable outcomes stand out.
- Better data and models. Years of testing produced robust curves linking speed, gap, and weight to fuel results. These inform today’s ADAS calibration, aero development, and convoy policies [NREL, 2014; NREL, 2018].
- Standards and interoperability. ENSEMBLE delivered a multi‑brand framework. SAE updated core V2V on‑board requirements in J2945/1C, laying groundwork for cooperative features beyond platooning [ENSEMBLE, 2022; SAE, 2024].
- Spectrum clarity and new pilots. FCC actions moved the ecosystem toward C‑V2X certainty. Corridor pilots like I‑70 now focus on leader‑follower automation that fits real lanes and duty cycles, with safety drivers and data collection front and center [FCC, 2020; FCC, 2024; DriveOhio/INDOT, 2025].
Platooning advanced the state of practice even if it did not scale quickly. The field learned where physics delivers, where operations get in the way, and how standards and spectrum shape timing. Great ideas need the right alignment to reach scale. The same discipline now benefits connected‑vehicle safety, ADAS, and autonomy programs that build on platooning’s data, tools, and human‑factors lessons [FHWA, 2021; ENSEMBLE, 2022].
Sources:
- [NREL, 2014] Lammert, M., Duran, A., Diez, J., Burton, K., Nicholson, A. “Effect of Platooning on Fuel Consumption of Class 8 Vehicles Over a Range of Speeds, Following Distances, and Mass.” National Renewable Energy Laboratory. 2014. docs.nrel.gov
- [NREL, 2018] McAuliffe, B. et al. “Influences on Energy Savings of Heavy Trucks Using Platooning in Real‑World Conditions.” NREL/TP‑70868. 2018. docs.nrel.gov
- [NREL, 2020] McAuliffe, B. et al. “Impact of Mixed Traffic on the Energy Savings of a Truck Platoon.” NREL/TP‑78218. 2020. docs.nrel.gov
- [FMCSA, 2018] Loftus, T., Tershak, D. “Truck Platooning.” FMCSA Research overview. 2018. fmcsa.dot.gov
- [FHWA, 2021] Foreman, C. “Truck Platooning.” FHWA‑HRT‑22‑007. 2021. fhwa.dot.gov
- [ENSEMBLE, 2022] “Platooning becomes a reality in Europe.” ENSEMBLE final results summary. 2022. connectedautomateddriving.eu
- [FCC, 2020] First Report and Order. “Use of the 5.850–5.925 GHz Band.” FCC 20‑164. 2020. docs.fcc.gov
- [FCC, 2024] Second Report and Order. C‑V2X technical rules in remaining 30 MHz. FCC 24‑123. 2024. docs.fcc.gov
- [SAE, 2024] SAE J2945/1C. “On‑Board System Requirements for V2V Safety Communications.” September 2024. sae.org
- [NCSL, 2025] National Conference of State Legislatures. “Autonomous Vehicles | State Laws.” 2025. ncsl.org
- [DriveOhio/INDOT, 2025] “Ohio and Indiana Deploy Partially Automated Trucks on I‑70.” Press release. April 14, 2025. drive.ohio.gov
- [Supply Chain Dive, 2019] Lopez, E. “Daimler: There is ‘no business case’ for truck platooning.” Jan. 8, 2019. supplychaindive.com